CMI (Creative Microsystems Inc): PAMC-500

Connection: CPU Socket

Processor:

68000@14Mhz switchable to 7Mhz

FPU:

Optional 68881 (a separate crystal must be obtained)

MMU:

None

Max Ram:

None

Ram Type:

Does not have support for adding RAM.

An accelerator board designed for the A500 which sits in the CPU
socket. This card is also compatible with the A2000 however it's
dimensions mean that it may hang over the A2000's battery requiring
some method to raise the card high enough. The PAMC-500 (unlike the
PAMC-2000) has special notches cut into the PCB to stop it hanging over
the Agnus, allowing for the Megachip to be installed. It still however
covers the Kickstart chips meaning you may have difficulty using a ROM
switcher. The card can be set to either 14Mhz or 7Mhz using the
software provided (PA), dropping to 7Mhz is to help with any backwards
compatibility problems. Replacement Workbench 1.3 maths libraries are
supplied (providing you are using WB1.3) to take advantage of the FPU
if one is fitted.

Jumpers

J1: Fast ROM

When the two jumper pins are shorted, the accelerator runs in "Fast
ROM" mode where the Kickstart ROM is accessed with a reduced number of
wait-states when the processor is running at 14Mhz. Some A500's and
A2000's with Kickstart 1.3 are not able to handle this feature, and the
jumper should be disabled.

J2: Forced 14 Jumper

Normally the PA program is used to switch the clock speed to 14MHz.
This can be done using a project icon, or added to the
startup-sequence. However, some self-booting games do not execute a
startup sequence, and some users wish to run at 14mhz at all times. The
jumper has 2 potitions, but pin 1 is not marked. Looking at the jumper
with the (Jumper) 2 identifier upright, the right and middle pins
jumpered will allow the processor to be switched between 7 and 14mhz
using the software. The middle and left pins jumpered will force the
processor to run at 14Mhz at all times.